1. Field of the Invention
The present invention relates to a microfluidic chip, and more particularly, to a microfluidic chip for a multiple bioassay that includes microfluidic channels and a method of manufacturing the microfluidic chip.
2. Description of the Related Art
A biochip which is formed by immobilizing biomolecule probes to be analyzed, such as DNA, protein or the like, on a support with high density can be used to analyze gene expression characteristics, gene defects, protein distribution, reaction pattern, or the like by detecting whether hybridization between a target material contained in a sample and the probes occurs. Biochips can be categorized into DNA chips, protein chips, and the like according to the kind of the probes. Biochips also can be categorized into microarray chips in which probes are immobilized on a solid support and microfluidic chips in which probes are immobilized on a microfluidic channel according to the probe immobilization location.
The microfluidic chip is also referred to as a lab-on-a-chip, which is a small chip by which all of assay processes, including sample injection, hybridization, and detection, can be automatically performed, and an outstanding high-end product that will replace flasks and experimental tubes in laboratories in the future. The microfluidic chip is composed of various materials, glass, quartz, plastic, silicon, or the like, and includes a plurality of intersecting microchannels which are as fine as hairs. Various complicate experiments can be simultaneously performed by flowing a fluid through the microchannels.
A bioassay platform using microfluidic channels can perform multiple tests at high speed and low costs. However, the bioassay platform raises concern about cross-contamination and problems in fluidic channel fabrication and probe immobilization processes. In order to solve problems arising during such processes, conventionally, a method of connecting channels after the immobilization of probes on a substrate (array-based microfluidic chip) has been used. However, there still are problems in the alignment of channels and immobilized probes, probability of probe damage by heat applied to connect the channels, and problems in the process of connecting the substrate with immobilized probes and channels. In addition, as illustrated in FIG. 1, a method of packing probe-immobilized beads after the fabrication of channels (bead-based microfluidic chip, U.S. Pat. No. 6,632,655) is also in use. However, this method also raises problems, such as a pressure drop, signal loss, sample loss, etc.
In addition, a micromosaic immunoassay device fabricated by patterning a substrate into a polydimethylsiloxane (PDMS) channel structure having a plurality of patterned cavities, as illustrated in FIG. 2, was developed. However, since an immunoassay is implemented through probe immobilization and sample injection while the PDMS channel structure is rotated by 90 degrees, the binding between the PDMS channel structure and glass slides is reversible, and a mold needs to be replaced. Furthermore, it is impossible to perfectly bind the PDMS channel structure and a glass slide after the surface treatment of the glass slide, a solution may leak.
Accordingly, the inventors of the present invention have made efforts to overcome such problems arising with the conventional techniques, confirmed that using a single-layered channel structure formed by immobilizing probes in a microfluidic channel using a polymer and having a blocking wall for preventing mixing of samples, a multi-bioassay can be performed using a plurality of samples, and completed the present invention.